Isocyanates modified for being provided with surfactant property, composition containing same, resulting coating

ABSTRACT

The invention concerns a compound of formula (I)                    
     in which m is to 0 or 1 Iso is the (poly)isocyanate radical (after elimination of an isocyanate function); R 10  is selected among: a negative charge; a hydrocarbon-based radical (i.e. a residue containing hydrogen and carbon atoms) having a carbon as it binding point [i.e. the atom carrying the open bond ]; R 11  is selected among: a negative charge. The invention is applicable to organic synthesis.

This application is an application under 35 U.S.C. Section 371 ofInternational Application Number PCT/FR98/00405, filed on Mar. 2, 1998.

The present invention relates to a family of isocyanates which aremodified to give them a surfactant property.

The present invention relates to isocyanate-based compounds andcompositions (which can be partially masked, but this is not thepreferred embodiment). The invention is also directed toward the processfor using them, their use for making coatings and the coatings thusobtained. The invention relates more particularly to compositions whichare (self)dispersible in aqueous phase.

In order to give a better understanding of the invention it has appearedappropriate to make the following reminders.

In the present description, the particle size characteristics oftenrefer to notations of the type d_(n) in which n is a number from 1 to99. This notation is well known in many technical fields, but isslightly rarer in chemistry, and it may thus be useful to recall itsmeaning. This notation represents the particle size such that n% (byweight, or more exactly by mass, since weight is not an amount of matterbut rather a force) of the particles is less than or equal to said size.

In the description hereinbelow, the polydispersity index will be used,which is defined as

I=(d ₉₀ −d ₁₀)/d ₅₀

In the paints and varnishes sector, diisocyanates are widely used, inparticular alkylene diisocyanates (for example those sold under thebrand Tolonate®) and derivatives thereof of biuret type or trimersthereof.

However, two problems remain incompletely solved to date, namely:

the use of organic solvents, whose presence is reputed to be toxic andharmful to the environment;

the need to provide on the market non-volatile products, which has ledto the molecules being made heavier, by oligomerizing the diisocyanates;this solution is not entirely satisfactory since it uses an elaborate,and thus expensive, function to solve the problem.

Needless to say, these problems must be solved while at the same timesatisfying the constraints intrinsic to coatings.

To make films of paints or of varnishes, a dispersion or an emulsioncontaining the isocyanate, which may be blocked, on the one hand, and adispersion or a solution of polyol, on the other hand, are mixedtogether.

The mixture of the dispersions, which can also contain pigments, inparticular titanium dioxide, the dispersion of which is improved by thepresent invention, and fillers, is then applied to a support in the formof a film with the aid of the standard techniques for using industrialpaints. When the preparation contains blocked isocyanates, the film plussupport assembly is cured at a temperature which is sufficient torelease the isocyanate functions and to condense them with hydroxylgroups of the polyol particles. However, it should be recalled thatmasked or blocked products have a significantly higher cost price thannon-masked products.

The use of organic solvents is increasingly being criticized by theauthorities in charge of safety at work, since these solvents, or atleast some of them, are reputed to be toxic or chronotoxic. For thisreason, efforts are being made to develop more and more techniques whichreplace the solvent-medium techniques in order to overcome the drawbacksassociated with solvents.

One of the solutions most frequently used lies in the use of emulsionsor dispersions in water. On account of the reactivity of water withisocyanates, this solution is especially used for masked isocyanates.

In order not to end up between Scylla and Charybdis, a major stumblingblock is to be avoided, namely the deterioration of one or more of theessential qualities of the coatings [smooth nature (to avoid the“orange-peel” appearance), hardness, resistance to solvents, etc.]; inparticular, poor adhesion of the coating to its support should befeared. The reason for this is that many surfactants are reputed toimpair the integrity of the link between the coating and its support andare known and used to undermine the attachment between a polymer and asupport (cf., for example DE-OS 3,108,537).

When unmasked or incompletely masked isocyanates are used, their useablelifetime remains less than a few hours, in general one or two hours.

Thus, it is important not to encounter any difficulties during theemulsification or dispersion of the isocyanates.

Accordingly, one of the aims of the present invention is to provide acompound and a composition which, by mixing in water or, morespecifically, in an aqueous phase, gives an emulsion without it beingnecessary therefor to use specific techniques and/or plants.

Another aim of the present invention is to provide a compound and acomposition of the above type which does not disrupt the coatingoperations.

Another aim of the present invention is to provide a compound and acomposition of the above type whose solvent content is less than ⅕,advantageously less than {fraction (1/10)}, on a mass basis relative tosaid composition. Needless to say, it is preferable for there to be aslittle solvent as possible, or even none at all.

These aims and others which will become apparent hereinbelow areachieved by means of compounds of formula (I) and of compositions, inwhich they comprise at least one compound of formula (I)

in which m is equal to zero or, advantageously, to 1;

in which Iso is a (poly)isocyanate residue (after removal of anisocyanate function);

in which R₁₀ is chosen from:

a negative charge;

a hydrocarbon-based residue (i.e. a residue containing hydrogen andcarbon atoms) whose point of attachment [i.e. the atom bearing the openbond] is a carbon;

in which R₁₁ is chosen from:

a negative charge;

a group of formula II:

in which R′₁₀ is chosen from hydrocarbon-based residues (similar to ordifferent from R₁₀) and a negative charge whose point of attachment[i.e. the atom bearing the open bond] is a carbon

in which R′₁₁ is (are) chosen from hydrocarbon-based residues whosepoint of attachment [i.e. the atom bearing the open bond] is a carbon(similar to or different from R₁₀ and R′₁₁) and a negative charge.

Although this does not form part of the preferred compounds, it shouldbe noted that when the similar or different organic substituents (R₁₀;R′₁₁; R′₁₀) do not comprise a polyethylene glycol chain fragment, it ispreferable for them to be C₈ to C₁₂ alkyl, advantageously branched, or aC₁₂ to C₁₆ aralkyl or a C₁₀ to C₁₄ alkylaryl.

It is desirable for at least one of the similar or different organicsubstituents (R₁₀; R′₁₁; R′₁₀) to contain a polyethylene glycol chainfragment advantageously of at least 5, preferably of at least 7,ethylene oxide units. In other words, it is desirable for at least oneof the organic substituents to correspond to the same formula as thesubstituents of E in the general formula I. More specifically, at leastone of the organic substituents (R₁₀; R′₁₁; R′₁₀) corresponds to theformula:

where R₅ represents an arm containing not more than two carbon-basedchain members where n is an integer chosen between 0 and 30,advantageously between 5 and 25, preferably between 9 and 20 (closedintervals, i.e. including the limits);

where R₁ represents a hydrocarbon-based radical advantageously chosenfrom optionally substituted aryls and alkyls.

Said lipophilic part R₁ is generally chosen from alkyl groups [in thepresent description alk-yl is taken in its etymological sense as thehydrocarbon-based residue of an alkan-ol after ignoring the alcohol (or-ol) function]; and aryl groups. When the number of ethylene glycolfunctions is not more than 5, the simple alkyls are advantageouslybranched, advantageously C₈ to C₁₂, the aralkyls are C₁₂ to C₁₆, thealkylaryls are C₁₀ to C₁₄ and the simple aryls are C₁₀ to C₁₆. If not,the lipophilic part can vary widely, especially when the number ofethylene glycol units is greater than 10, and can thus constitute ahydrocarbon-based radical of at least 1, advantageously of at least 3,and containing not more than 25, advantageously not more than 20, carbonatoms.

It is advantageous for the Iso radical to afford, predominantly ortotally, an aliphatic bond with the same preferences as those outlinedabove with regard to the isocyanates.

These compounds are derived from the decarboxylative condensation ofisocyanate, which is advantageously aliphatic, with partiallyneutralized phosphoric acid and phosphates.

The compounds of formula:

in which R₁₀ and R₁₁ can take the above values, but also, when m is 1,can be a negative charge on account of the fact that there may besignificant amounts of residual phosphoric acid in certain batches, thusalso form part of the invention.

Needless to say, R₁₀ can then also be equal to:

The Iso radical may or may not then be the same as that of thepenultimate formula,

in which Iso represents a polyisocyanate residue, advantageously theresidue of a product of reaction of a diisocyanate monomer to formbiuret or isocyanurates (trimer) or with a di- or polyol, advantageouslya triol or a tetraol.

It is advantageous for the Iso radical to afford, predominantly ortotally, an aliphatic bond with the same preferences as those outlinedabove with regard to the isocyanates.

In addition to the function featured in the formula, Iso advantageouslybears at least one, and preferably at least two, isocyanate functions,preferably at least one of which is not masked and more preferably atleast two of which are not masked.

However, according to a preferred embodiment of the present invention,it has been shown that it may be advantageous to replace most or evenall of the isocyanate functions with those specified above. This gives acompound which is both stable and inert with respect to isocyanatecompositions, which can be added to the isocyanate compositions withoutany specific precaution.

The preferred isocyanates for the complete reaction above arelow-viscosity isocyanates, especially aliphatic isocyanates; mention maybe made in particular of the simple monomer, preferably of polymethylenediisocyanate and advantageously hexamethylene diisocyanate, andderivatives of the “trimerization” reaction which gives di-, tri-,tetra-, penta-, hexa- or heptafunctional isocyanates, advantageouslytrifunctional isocyanates.

A subject of the present invention is also compositions comprising atleast one compound of formula (I).

More specifically, they comprise, in particular:

a sub-composition which is a vector of isocyanate functions, thepreferred characteristics of which will be specified later, and

a surfactant containing at least one compound of formula (I);

optionally, an aqueous phase.

Thus, according to one advantageous variant of the present invention,the compositions according to the present invention comprise compoundsderived from the reaction outlined above in an overall proportion,relative to a volume of one liter of isocyanate, of from 0.01 to 1,advantageously from 0.05 to 0.5 and preferably from 0.05 to 0.3,equivalent of function:

in which m is equal to zero or 1.

According to the present invention, said compound can be used alone oras a mixture with one or more surfactants. These surfactants can beagents also corresponding to formula (I).

These optional surfactants can also be chosen from other ionic compounds[in particular aryl and/or alkyl sulfate(s) or phosphate(s) (obviously,aryl in particular encompasses alkylaryls and alkyl in particularencompasses aralkyls), aryl or alkyl phosphonate, phosphinate orsulfonate, fatty acid salt and/or zwitterionic salt] and from nonioniccompounds which may or may not be blocked at the end of the chain(however, the nonionic compounds containing alcohol functions on atleast one of the chains appear to have a slightly unfavorable effect onthe (self)emulsion, although they have a favorable effect on otheraspects of the paint composition; taking all of this into account, it ispreferable that the content of this type of compound should representnot more than one-third, advantageously not more than one-fifth,preferably not more than one-tenth, of the mass of said anioniccompounds according to the invention).

The countercation is advantageously monovalent and is chosen frominorganic cations and organic cations that are advantageouslynon-nucleophilic and, consequently, of quaternary or tertiary nature (inparticular oniums from column V, such as phosphonium, ammoniums, or evenfrom column VI, such as sulfonium, etc.) and mixtures thereof, usuallyammoniums, generally derived from an amine, advantageously a tertiaryamine. Advantageously, an organic cation containing a hydrogen which isreactive with the isocyanate function is avoided. This results in apreference for tertiary amines.

The inorganic cations can be sequestered by phase-transfer agents suchas crown ethers.

The pKa of the cations (organic [ammonium, etc.] or inorganic) isadvantageously between 8 and 12.

The cations, and in particular the amines, corresponding to theammoniums, advantageously have no surfactant property, but it isdesirable that they should have good solubility, or in any casesufficient solubility to ensure that of said compounds of formula (I)anionic and advantageously a polyethylene glycol chain fragment, inaqueous phase and at the working concentration. Tertiary aminescontaining not more than 12 carbon atoms, advantageously not more than10 carbon atoms, preferably not more than 8 carbon atoms, per “onium”function (it is reminded that there is preferably only one of these permolecule) are preferred. The amines can contain other functions, and inparticular functions corresponding to amino acid functions and cyclicether functions such as N-methylmorpholine, or otherwise. These otherfunctions are advantageously in a form which does not react with theisocyanate functions and does not significantly impair the solubility inaqueous phase.

It is very desirable for the anionic compounds according to the presentinvention to be in a neutralized form, such that the pH induced during adissolution or a placing in contact with water is at least equal to 3,advantageously to 4, preferably to 5, and not more than 12,advantageously not more than 11, preferably not more than 10.

The mass ratio between the surfactant compounds (including said compoundof formula (I)) and the isocyanates is very preferably between 4 andabout 10%; the recommended zones will be explained later.

The composition can also comprise a catalyst, advantageously a latentcatalyst (which can be released by the action of external agents, forexample visible or UV radiation, oxygen).

The isocyanate composition according to the invention can, afterdispersion or emulsification in an aqueous phase, comprise a watercontent of from 10 to 70%. The emulsion is an oil-in-water emulsion.

However, in the course of the study which led to the present invention,in particular in the case of aliphatic isocyanates (i.e. isocyanatesconnected to the hydrocarbon-based skeleton (i.e. a skeleton containingboth hydrogen and carbon) via a saturated (sp³) carbon), it has beenshown that there is a risk of various reactions getting out of controlwhen certain proportions of water are reached. Thus, it is recommendedto avoid compositions in which the mass ratio between the amount ofwater in the aqueous phase, on the one hand, and the sum of theisocyanate and the surfactant according to the invention, on the otherhand, is between 10⁻² and 0.5. If greater safety is desired, ratiosbetween 10⁻³ and 1 will be avoided.

The emulsions obtained have, for the isocyanate part, d₅₀ values atleast equal to 0.1 micrometer, usually 0.5 micrometer, and they have ad₅₀, preferably a d₈₀ advantageously less than or equal to (at mostequal to) 5 micrometers, preferably 3 micrometers.

The aqueous phase of the emulsion generally serves as a vector for theco-reagents which are polycondensable with the isocyanate functions and,in this case, comprises compounds containing functions (advantageouslynot more than 4, preferably not more than 3 functions; cf. theexplanation below for the polyols which general mutatis mutandis to allthe functionality of this type) bearing reactive hydrogens, in generalone or more polyols.

This polyol is a polymer which contains at least two hydroxyl groups(phenol or alcohol) advantageously having a hydroxyl content of between0.5 and 5%, advantageously between 1 and 3% (by mass). With theexception of the latices which will be recalled below, it advantageouslycomprises not more than 4, and preferably not more than 3, primaryalcohol functions (but usually two since the actual crosslinking[brought about by a functionality statistically greater than two(fractional value possible)] is generally generated by thepolyisocyanates). However, it may also comprise secondary or tertiaryalcohol functions (in general not more than about 10, advantageously notmore than 5 and usually not more than two), which, in general, do notreact or react only after the primary alcohol functions, and in theorder: primary, secondary, tertiary.

Polyoses or polyosides (starch, cellulose, various gums (guar, carob,xanthan, etc.)), especially in solid form, are to be avoided. In theform of a texturing agent, and provided that this does not harm theemulsification or emulsion stability, they can, however, be used to givespecific properties (for example thixotropic properties, etc.). Thepolymer skeleton can be of varied chemical nature, in particularacrylic, polyester, alkyd, polyurethane or even amide, including urea.

The polyol can comprise anionic groups, in particular carboxylic orsulfonic groups, or can comprise no ionic groups.

In the context of the present invention, it has been shown that thepresent of an anionic carboxylate function (—CO₂—) significantlyincreases the drying kinetics, which is particularly advantageous forobtaining rapid “dust-free” drying, in particular when operatingexternally. A significant effect can be noted for a ratio of at leastone carboxylic function to approximately 20 functions containingreactive hydrogen [alcohol or phenol function], advantageously for aratio of one to about 10, preferably for a ratio of one to about 5;however, it is desirable for this ratio to be at most equal to onefunction to one function, preferably one carboxylic function to two olfunctions. The carboxylate countercations advantageously satisfy thesame preferences as those explained for the countercations in thecompound according to the present invention.

The polyol can already be in aqueous or water-soluble orwater-dispersible medium.

This can be an aqueous solution (which can be obtained in particularafter neutralization of the ionic groups) or an emulsion of the polymerin water or a latex-type dispersion.

It appears to be possible to disperse a standard polyisocyanate in awater-soluble polyol under certain formulation conditions (in particularwith a suitable ratio of pigment to paint binder). However, the use ofstandard polyisocyanates with water-dispersed polyols (such as resin orlatex emulsions) often poses problems of incompatibility (flocculation,appearance of several phases, etc.). One of the many advantages of thepreparation according to the invention is that it offers great freedomof choice for the formulation (physical form of the polyol, ratio ofpigment to binder, ease of incorporation into aqueous media).

Moreover, it has been found through the typical values of coatings (inparticular chemical resistance and hardness), that the crosslinking ofthe films is much greater when the polyol used is carboxylated.

In particular, it is advantageously possible to use latices, especiallynanolatices (i.e. latices whose particle size is nanometric [morespecifically whose d₅₀ value is at most equal to about 100 nanometers]).

Thus, according to one of the particularly advantageous embodiments ofthe present invention, the polyol is advantageously a nanometer-sizedlatex which has the following characteristics:

d₅₀ of between 15 and 60 nm, advantageously between 20 and 40 nm

carboxylate function of 0.5 to 5% by mass

-ol function: between 1 and 4%, advantageously between 2 and 3%

solids content: between 25 and 40%

a d₈₀ value of less than 1 micrometer.

In addition, especially when their glass transition temperature is lessthan 0° C., advantageously less than −10° C. and preferably less than−20° C., the latices allow high-quality resistance to bad weather and inparticular to temperature variations to be obtained, even with aromaticisocyanates.

The molar ratio between the free isocyanate functions and the hydroxylfunctions is between 0.5 and 2.5, advantageously between 0.8 and 1.6,advantageously between 1 and 1.4.

The latices (not functionalized with isocyanate, optionally masked)described in the French patent application filed on Apr. 28, 1995, No.95/05123, and in the corresponding European patent application No. EP0,739,961, give very good results.

Thus, advantageously, the latex particles have an accessible acidfunction (advantageously carboxylic acid function) content of between0.2 and 1.2 milliequivalent/gram of solid material and they have anaccessible alcohol function content of between 0.3 and 1.5milliequivalent/gram.

Thus, as indicated in this document, the preferred latices are thoseconsisting of particles bearing function(s) according to the invention,are hydrophobic and advantageously have a size (d₉₀) generally ofbetween 0.01 micrometer and 10 micrometers and preferably not more than5 micrometers, or even 2 micrometers. They are calibrated, monodisperseand present in the latex in a proportion ranging between 0.2 and 65% byweight relative to the total weight of the latex.

The weight-average molecular mass (M_(w), preferably determined by gelpermeation chromatography, known as “GPC”) of the polymers constitutingthe particles of population A (latex containing an -ol function actingas polyol) is advantageously between 5×10⁴ and 5×10⁶, preferably 1.1×10⁵and 2×10⁶.

The alcohol functions or the acid, preferably carboxylic acid, functionscan also be obtained by hydrolysis of alcohol-generating functions(ester, ether, halide, etc.) or acid-generating functions (ester,anhydride, acid chloride, amide, nitrile, etc.).

The distribution between the various types of units advantageouslysatisfies the following rules:

The content of unit derived from the monomer consisting of said freealcohol containing an activated ethylenic function, and relative to thetotal amount of units of any kind, is advantageously between 3 and 15%,preferably between 4 and 10% (mole or equivalent).

According to one advantageous embodiment of the present invention, theunit is derived from an ester of an α-ethylenic acid with a diol, one ofthe alcohol functions of which remains non-esterified. Said diol isadvantageously an ω/ω′ diol, advantageously chosen from 1,4-butanediol,1,3-propanediol and glycol.

It is desirable for said α-ethylenic acid to be an optionallysubstituted acrylic acid.

According to one preferred embodiment of the present invention, thecontent of unit derived from a free carboxylic acid (or in the form ofone of its salts), and relative to the total amount of units of anykind, is between 2 and 10% (mole).

For economic reasons, it is often advantageous for said free acid to bean optionally monosubstituted acrylic acid or one of its salts.

The particles obtained from the present invention can consist of twoseparate polymers, the first constituting the core and the secondconstituting the periphery. This type of particle can be obtained byepipolymerization [in which a latex seed is coated by surfacepolymerization (epipolymerization, occasionally referred to assuperpolymerization)] of a separate polymer. The core is occasionallyknown as the seed by analogy with the phenomenon of crystallization. Inthis case, only the second polymer, i.e. the surface polymer, satisfiesthe concentration constraints for the various functions according to thepresent invention.

These optional surfactants can also be chosen from other ionic compounds[in particular aryl and/or alkyl sulfate(s) or phosphate(s) (obviously,aryl in particular encompasses alkylaryls and alkyl in particularencompasses aralkyls), aryl or alkyl phosphonate, phosphinate orsulfonate, fatty acid salt and/or zwitterionic salt] and from nonioniccompounds which may or may not be blocked at the end of the chain(however, the nonionic compounds containing alcohol functions on atleast one of the chains appear to have a slightly unfavorable effect onthe (self)emulsion, although they have a favorable effect on otheraspects of the paint composition; taking all of this into account, it ispreferable that the content of this type of compound should representnot more than one-third, advantageously not more than one-fifth,preferably not more than one-tenth, of the mass of said compounds offormula (I) according to the invention).

According to one particularly advantageous embodiment of the presentinvention, after dispersion or emulsification, the sum of theconstituents in the binder (i.e. the mass contents of the isocyanate(s),emulsifier(s) and polyol(s)) in water ranges from 30 to 70% relative tothe total amount of the composition.

The isocyanates targeted by the invention in particular comprise thecompounds detailed below.

These compounds can advantageously contain the structures common in thisfield, for example prepolymers derived from the condensation of polyol(for example trimethylol propane), in general triol (which isadvantageously primary, see later regarding the definition of thepolyols) and especially the most common structures, i.e. those ofisocyanurate type, also known as trimer, uretidine dione structures,also known as dimer, biuret or allophanate structures or a combinationof structures of this type on a single molecule or as a mixture.

If it is desired to lower the solvent content of the compositionsubstantially, in particular when it is in emulsion form, it ispreferable to use mixtures of this type which naturally (i.e. withoutaddition of solvent) have a low viscosity. The compounds with thisproperty are especially the derivatives (such as isocyanurate, alsoknown as trimer, uretidine dione structures, also known as dimer, biuretor allophanate structures or a combination of structures of this type ona single molecule or as a mixture), partial and/or total, of thealiphatic isocyanates whose isocyanate functions are connected to theskeleton via ethylene fragments (for example polymethylenediisocyanates, in particular hexamethylene diisocyanate and thosearylenedialkylene diisocyanates whose isocyanate function is remote fromthe aromatic rings by at least two carbons, such as(OCN—[CH₂]_(t)—Φ—[CH₂]_(u)—NCO) with t and u greater than 1). Thesecompounds or mixtures advantageously have a viscosity at most equal toabout 3000 centipoises (or millipascal.seconds), preferably to about1500 centipoises (or millipascal.seconds).

When these values are not reached, it is then often useful to bring themixture to these viscosity values by adding a minimum amount of suitablesolvent(s). As already mentioned above, the isocyanates concerned can bemono-, di- or even polyisocyanates. Advantageously, these derivativescan contain structures of isocyanurate type, also known as trimer,uretidine dione structures, also known as dimer, biuret or allophanatestructures or a combination of structures of this type on a singlemolecule or as a mixture.

The isocyanate monomers can be:

aliphatic, including cycloaliphatic and arylaliphatic, such as:

like simple aliphatic, polymethylene diisocyanates and in particularhexamethylene diisocyanate;

like partially aliphatic “neopentyl” partially cyclic (cycloaliphatic)isophorone diisocyanate (IPDI);

like cyclic aliphatic (cycloaliphatic) diisocyanate, those derived fromnorbornane;

arylenedialkylene diisocyanates (such as OCN—CH₂—Φ—CH₂—NCO, a portion ofwhich shows no essential difference from the aliphatics, i.e. thosewhose isocyanate function is remote from the aromatic rings by at leasttwo carbons, such as (OCN—[CH₂]_(t)—Φ—[CH₂]_(u)—NCO) with t and ugreater than 1;

or aromatics, such as tolylene diisocyanate.

The preferred polyisocyanates targeted by the technique of the inventionare those in which at least one, advantageously two, preferably three,of the conditions below are satisfied:

at least one, advantageously at least two, of the NCO functions areconnected to a hydrocarbon-based skeleton via a saturated (sp³) carbon,preferably with at least one, preferably at least two, of thesub-conditions below:

at least one, advantageously two, of said saturated (sp³) carbons bearsat least one, advantageously two, hydrogen(s), (in other words, it hasbeen found that better results are obtained when the carbon bearing theisocyanate function bears a hydrogen, preferably two hydrogens);

at least one, advantageously two, of said saturated (sp³) carbons arethemselves borne by a carbon, which is advantageously aliphatic (i.e. ofsp³ hybridization), which itself bears at least one, advantageously two,hydrogen(s); in other words, it has been found that better results areobtained when the carbon bearing the isocyanate function is not in aso-called “neopentyl” position;

all the carbons via which the isocyanate functions are connected to thehydrocarbon-based skeleton are saturated (sp³) carbons whichadvantageously partly, preferably totally, bear a hydrogen, preferablytwo hydrogens; in addition, it is advantageous for said saturated (sp³)carbons themselves to be at least partially (advantageously one-third,preferably two-thirds), preferably totally, borne by a carbon,advantageously an aliphatic carbon (i.e. a carbon of sp³ hybridization),which itself bears at least one, advantageously two, hydrogen(s); inother words, it has been found that better results are obtained when thecarbon bearing the isocyanate function is not in a so-called “neopentyl”position;

particularly suitable polyisocyanates are those which contain, at leastpartially, an isocyanuric or biuret skeleton (whether this skeleton isderived from only one or from several monomers, see below) and morespecifically structures such as isocyanurate, also known as trimer,uretidine dione structures, also known as dimer, biuret or allophanatestructures or a combination of structures of this type on a singlemolecule or as a mixture.

When the polyisocyanates are relatively heavy, i.e. when they compriseat least 4 isocyanate functions, the first two conditions become:

at least one-third, advantageously two-thirds, of the NCO functions areconnected to a hydrocarbon-based skeleton via a saturated (sp³) carbon;

at least one-third, advantageously two-thirds, of said saturated (sp³)carbons bears at least one, advantageously two, hydrogen(s), (in otherwords, it has been found that better results are obtained when thecarbon bearing the isocyanate function bears a hydrogen, preferably twohydrogens); in addition, it is advantageous for said saturated (sp³)carbons themselves to be at least partially (advantageously one-third,preferably two-thirds), preferably totally, borne by a carbon,advantageously an aliphatic carbon (i.e. a carbon of sp³ hybridization),which itself bears at least one, advantageously two, hydrogen(s); inother words, it has been found that better results are obtained when thecarbon bearing the isocyanate function is not in a so-called “neopentyl”position.

Another aim of the present invention is to provide a process of theabove type which makes it possible to emulsify the composition targetedabove when it contains no water.

This aim and others which will become apparent hereinbelow are achievedby means of an emulsification process which comprises at least thefollowing step:

addition, advantageously with very moderate stirring, of theisocyanate(s) to the polyol+water mixture.

The surfactant can be either in the aqueous phase or, preferably, in theisocyanate phase. In the first case, the reactions between isocyanateand said compound comprising an anionic function and advantageously apolyethylene glycol chain fragment are much more limited.

This stirring is preferably manual or mechanical.

This emulsification is advantageously conducted at a temperature below50° C., preferably at room temperature.

It is desirable, if necessary, to adjust the pH (to reach a valueadvantageously at least equal to three, preferably 4, and advantageouslynot more than 11, preferably 10, and thus advantageously between 3 and11, preferably between 4 and 10) during the emulsification. Thisadjustment makes it possible to arrive at an advantageous zone in whichthe first (or only) acidity of each surfactant according to the presentinvention is neutralized.

According to one advantageous variant of the present invention, thepigments (and in particular the titanium dioxide) are dispersed in thepolyol(s) before addition of the isocyanate.

Another aim of the present invention is to provide a process forapplying the isocyanate-based composition to form a coating.

These aims and others which will become apparent hereinbelow areachieved by means of a process comprising the application of apreparative coat (i.e. a coat of composition according to the inventioncomprising the aqueous phase and the constituents of the coat) whosethickness before drying is between 10 and 400 micrometers,advantageously between 50 and 200 micrometers, corresponding, afterdrying, to a thickness of between 5 and 150 micrometers, advantageouslybetween 20 and 80 micrometers.

According to one advantageous embodiment, this process comprises adrying operation from 20° C. to 60° C. for a period which can range from¼ to 24 hours.

Advantageously, this drying operation takes place in the presence of asolvent to assist the removal of water.

According to one particularly advantageous embodiment of the presentinvention, the application is performed by spraying.

The preparation of the surfaces is well known to those skilled in theart (for example phosphatations for ferrous steel compounds orchromation for alumina-based surfaces) (reference may be made, forexample, to the following books: “Organic Coating Technology” Volume IIby H. F. Payne and “Paint Handbook” edited by G. E. Weismantel).

According to the present invention, it is thus possible to obtaincoatings (in particular paints or varnishes) which have the followingtechnical characteristics (these values depend especially on the polyolsused):

Implementation and characteristics of the coating Iso2178 dry thickness:45 μm Support and treatment thereof: steel treated by phosphatation:R461 plates from the supplier Q Pannel Minimum properties obtained UsualDIN test 67530 (these values are only of interest when a gloss paint isdesired, but not when a matt or satin paint is desired) 20° gloss 0.5 8060° 0.5 90 Konig Iso 1522 hardness 10s 150s DIN 53151 adhesion test GT-1GT-5 Impact strength test No. Iso 6272 direct 10 cm >100 cm inverse 5cm >100 cm Resistance to methyl, ethyl 20 >200 ketone (butanone)(Passage twice) External QUV content DIN 53384 50 h 800 h

The nonlimiting examples below illustrate the invention.

EXAMPLE 1

Synthesis of HDT isocyanate whose functions are totally converted intocompound according to the invention (reference CMI 972).

114 g of Rhodafac RE 610 are loaded into a three-necked flask. 26.3 g oftriethylamine are then added with stirring. The temperature of thereaction medium then rises from 21.8° C. to 39.6° C. 30 g of TolonateHDT with an NCO titer equal to 0.521 are then added at 31.5° C. Thetemperature of the reaction medium rises to 37° C.

After reaction for 2 hours after addition of the Tolonate, thetemperature of the reaction medium is 29.4° C. Infrared analysis on asample indicates the presence of isocyanate functions. After reactionfor three hours, infrared analysis of a sample indicates the presence offree isocyanate functions. 7 g of Rhodafac RE 610 mixture neutralizedwith triethylamine are then added in the same ratio as indicated above.After reaction for 4 h 40 min after addition of the Tolonate, infraredanalysis of a sample indicates the absence of free isocyanate functions.

The product is then stored in a 250 ml flask and used in the tests ofaqueous emulsification of polyisocyanates.

EXAMPLE 2

Emulsification of the reference product CMI 972 of composition suchthat:

RE 610 pre-neutralized with TEA

HDT/RE 610 ratio=1/1 molar (30 g of HDT+114 g of RE 610+26 g of TEA)

The 90/10 (by weight) HDT/CMI 972 mixture is selfemulsifiable (0.96 μmSYMPATEC).

The coatings obtained using this emulsion are of high quality.

What is claimed is:
 1. A composition of matter comprising: (a) asub-composition comprising isocyanate functions; (b) a surfactantcontaining a compound, having the following formula (I):

wherein: m is equal to 0 or 1; Iso is a (poly)isocyanate residue afterremoval of an isocyanate function; R₁₀ is a negative charge or a residuecontaining hydrogen and carbon atoms whose point of attachment is acarbon atom; and R₁₁ is a negative charge or a grout of formula II:

wherein R′₁₀ is a residue containing hydrogen and carbon atoms, or anegative charge whose point of attachment is a carbon and wherein R′₁₁is a residue containing hydrogen and carbon atoms whose point ofattachment is a carbon atom, or a negative charge; and, optionally, (c)an aqueous phase.
 2. A composition according to claim 1, comprising,relative to a volume of one litre of isocyanate(s), a quantity of 0.01to 1 equivalent of function of formula:

wherein: m is equal to 0 or 1; R₁₀ is a negative charge or a residuecontaining hydrogen and carbon atoms whose point of attachment is acarbon atom; and R₁₁ is a negative charge or a group of formula II:

wherein R′₁₀ is a residue containing hydrogen and carbon atoms, or anegative charge whose point of attachment is a carbon and wherein R′₁₁is a residue containing hydrogen and carbon atoms whose point ofattachment is a carbon atom, or a negative charge.
 3. A compositionaccording to claim 2, comprising from 0.05 to 0.3 equivalent of functionof formula:


4. A composition according to claim 1, wherein said sub-composition (a)comprises, on a mass basis, at least 5%, of isocyanate function.
 5. Acomposition according to claims 1, wherein said sub-composition (a)comprises, on a mass basis, not more than about 50%, of isocyanatefunction.
 6. A composition according to claims 4, wherein saidsub-composition comprises, on a mass basis, at least 15%, and not morethan about 30%, of isocyanate function.
 7. A composition according toclaim 1, wherein said sub-composition (a) is formed from aliphaticisocyanates.
 8. A process for making a coating, comprising the steps of:(1) applying a coating of a composition as defined in claim
 1. 9. Aprocess according to claim 8, further comprising the step of: (2) dryingsaid coating at a temperature of 20° C. to 50° C. for ¼ to 3 hours. 10.A process according to claim 9, wherein step (2) is carried out in thepresence of a solvent to assist the removal of water.
 11. A processaccording to claim 8, wherein step (1) is carried out by spraying or bymeans of a screw-rod applicator.
 12. A composition of matter accordingto claim 1, wherein Iso bears at least one other function of thefollowing formula:

wherein: m is equal to 0 or 1; R₁₀ is a negative charge or a residuecontaining hydrogen and carbon atoms whose point of attachment is acarbon atom; and R₁₁ is a negative charge or a group of formula II:

wherein R′₁₀ is a residue containing hydrogen and carbon atoms, or anegative charge whose point of attachment is a carbon and wherein R′₁₁is a residue containing hydrogen and carbon atoms whose point ofattachment is a carbon atom, or a negative charge.
 13. A composition ofmatter according to claim 1, wherein Iso bears at least two otherfunctions of the following formula:

wherein: m is equal to 0 or 1; R₁₀ is a negative charge or a residuecontaining hydrogen and carbon atoms whose point of attachment is acarbon atom; and R₁₁ is a negative charge or a group of formula II:

wherein R′₁₀ is a residue containing hydrogen and carbon atoms, or anegative charge whose point of attachment is a carbon and wherein R′₁₁is a residue containing hydrogen and carbon atoms whose point ofattachment is a carbon atom, or a negative charge.
 14. A composition ofmatter according to claim 1, being an isocyanate, wherein all of theisocyanate functions are converted into functions of the formula:

wherein: m is equal to 0 or 1; R₁₀ is a negative charge or a residuecontaining hydrogen and carbon atoms whose point of attachment is acarbon atom; and R₁₁ is a negative charge or a group of formula II:

wherein R′₁₀ is a residue containing hydrogen and carbon atoms, or anegative charge whose point of attachment is a carbon and wherein R′₁₁is a residue containing hydrogen and carbon atoms whose point ofattachment is a carbon atom, or a negative charge.
 15. A composition ofmatter according to claim 1, being an isocyanate, wherein all of theisocyanate functions are converted into functions of the formula:

wherein: m is equal to 0 or 1; R₁₀ is a negative charge or a residuecontaining hydrogen and carbon atoms whose point of attachment is acarbon atom; and R₁₁ is a negative charge or a group of formula II:

wherein R′₁₀ is a residue containing hydrogen and carbon atoms, or anegative charge whose point of attachment is a carbon and wherein R′₁₁is a residue containing hydrogen and carbon atoms whose point ofattachment is a carbon atom, or a negative charge; and wherein saidisocyanate is di-, tri-, tetra-, penta-, hexa- or heptafunctional withisocyanate function.
 16. A composition of matter according to claim 1,wherein said isocyanate is an aliphatic isocyanate.
 17. A composition ofmatter according to claim 1, wherein said isocyanate is a prepolymer ofdifunctional aliphatic isocyanates.
 18. A composition of matteraccording to claim 17, wherein the prepolymer bears an isocyanurategroup, an uretidine dione structure, a biuret, or an allophanatestructure.
 19. A composition of matter according to claim 18, whereinthe prepolymer bears an isocyanurate group and an uretidine dionestructure.
 20. A composition of matter according to claim 17, whereinthe prepolymer is a difunctional isocyanate selected from the groupconsisting of aliphatic diisocyanates, cycloaliphatic diisocyanates, andarylenedialkylene diisocyanates.
 21. A composition of matter accordingto claim 20, wherein the difunctional isocyanate is a polymethylenediisocyanate or an isophorone diisocyanate.
 22. A composition of matteraccording to claim 21, wherein the difunctional isocyanate ishexamethylene diisocyanate.
 23. A composition of matter according toclaim 17, wherein said isocyanate comes from biurets and from trimers ofpolymethylene diisocyanates by replacement of the isocyanate functionswith functions of the formula;

wherein: m is equal to 0 or 1; R₁₀ is a negative charge or a residuecontaining hydrogen and carbon atoms whose point of attachment is acarbon atom; and R₁₁ is a negative charge or a group of formula II:

wherein R′₁₀ is a residue containing hydrogen and carbon atoms, or anegative charge whose point of attachment is a carbon and wherein R′₁₁is a residue containing hydrogen and carbon atoms whose point ofattachment is a carbon atom, or a negative charge.